In a network including a plurality of nodes and multiple links connecting between the nodes, a flow setting request between nodes (a source node and an destination node) is made in order to send data from a certain terminal to a destination terminal. As used herein, the “flow” is a data flow, and can also be referred as a session or a path. By means of the flow setting request, a route design system operating on a network management system (NMS) that is connected to the respective nodes in the network and manages and controls each node determines an optimal route in the network and accommodates the flow in the determined route.
Conventionally, in order to determine the optimal route, a technique has been proposed in which the route that has the smallest total cost is determined based on objective function (MIN {ΣiΣjLi, j}, where Li, j are link cost values representing the link from the node i to the node j), based on “costs” defined for the links defining the respective routes in accordance with the traffic volume (see Patent References 1 and 2, for example).
The cost, as used herein, is a physical quantity born by each node for traffic processing for the respective flow, concrete examples of which include the transmission power, the reception power, the band of the link, the subscription fee charged for usage of the link.
In addition, in the environment in which each nodes has a DVS (Dynamic Voltage Scaling) feature for controlling the power consumption in accordance with the traffic volume, it has been proposed to give a link cost value corresponding to the power consumptions of the nodes and calculate the minimum cost route (see Patent Reference 3, for example).